There are two schools of thought on teakmaintenance. Some like the brown look and others like the grey look. I prefer grey so I'll be telling you how to keep the grey.

Start with a good scrub with hot water and soap and a stiff bristle brush then rinse clean. See what that does to the marks because it might be enough.

If more is needed then grab a cup of white vinegar and a scotch brite pad and scrub not just the stains but the entire area around them. You are doing this to get an even color rather that a funny looking bleached section where the stains were. Rinse, dry and inspect. It might be necessary to repeat the vinegar scrub if the stains are really bad.

The teak should stay grey with just one vinegar scrub but if you need two then you can expect a color change. No matter what you do there will be less damage than a teak cleaner will cause. That stuff is too aggressive and if used repeatedly will cut the life of your teak in half. Teak cleaner is usually an oxalic acid mix which literally melts away the top layer of your teak. Vinegar is a cheaper and milder alternative.

If you like the brown look of teak then go ahead and use the commercial products. If your teak lasts 10 years you will have done well.

i second the usage of bleach with soap to clean the teak. would hesitate to use acid (even vinegar) though. i find that mildew is a problem in florida and the bleach does a good job with that and also on non skid decks. rinse after scrubbing.

__________________sometimes the things that may or may not be true are the things a man needs to believe in the most.

One very important thing to remember if you are going to scrub a teak deck is never to scrub in the direction of the grain as this can rip the soft lighter coloured grained timber which degrades the surface and can leave it rough. Always brush across the grain and do not apply undue pressure.

If this is only a little oil, I'd try using any vegetable oil, to break it up a bit, then regular dishwashing detergent to clean that area. Where fender grunge is, that you can dissolve with acetone. The latter will leave your teak too clean, and it will need a little tung oil added to those spots, like a tiny bit, rubbed in with a rag.

If you don't get the results you want that way, then use teak wonder products, but you have to keep it up, and it's expensive. If you use Deks Olje, it will eat out the soft grain of the wood.

If you let it go grey (God's will, perhaps), you will have less strife with it. All your choice.